Direct current electricity could cut power bills, claims creator

The creator of a home electricity system that uses direct current claims it could cut users’ bills by up to 30 per cent.

Moixa Technology this week unveiled its Smart DC network, which uses solar panels and off-peak grid electricity stored in batteries to power electronic devices in the home such as televisions, laptops, mobile phones and LED lighting.

This reduces energy losses associated with converting alternative current from mains sockets into DC (up to 45 per cent), which most small electronic devices run on, or with converting DC generated by solar panels into AC to sell to the grid (up to 15 per cent).

The network comprises solar panels, DC sockets, an electric vehicle-quality Li-Fe battery — that could power LED lights in a typical house during a power cut for a day — and a hub device that takes information from a smart meter.

This hub manages the flow of electricity according to how much energy it predicts the house will need, how much is available from the solar panels and battery and how much grid power costs according to whether it is a peak or off-peak period.

It can also use weather information to predict how much solar power it will generate the following day and store grid energy in the battery accordingly.

‘People just want cheap and efficient energy,’ Simon Daniel, chief executive officer of Moixa, told The Engineer. ‘Too much information is annoying but people will take good advice if it is specific to their situation.’

Users could save between 10 and 30 per cent on their electricity bills, he added, and an additional 15 to 20 per cent on their gas bills by adding an electronic boiler monitor that predicts gas usage and turns off the heating when it’s not needed.

The company plans to follow a business model similar to that of Sky, making the technology easy to install by local contractors and offering gradual upgrades than can be added easily.

The network will also use data on the changing price of solar panels and LED lighting decreases to tell the homeowner when it becomes cost-effective for them to install more of these products.

Moixa is aiming to make the system available for between £1,000 and £3,000 per home. Daniel estimated this cost could be recouped in three to five years through savings on energy bills.

The firm expects the system to be of particular interest to those who work from home and operate electronic devices throughout peak hours, as well as to hotels and student accommodation.

Smart DC was developed following £1.4m of research projects led by Moixa and funded by the Technology Strategy Board and the EU.

Readers' comments
(29)

Ian Poskitt | 13 Oct 2011 3:09 pm

I absolutely agree with this idea. I plan to run all those things that require a low v dc such as cordless phone, mobile charger, router, burglar alarm, door bell, printer, etc. Then get rid of all the 13A plug top PSUs which sit there 24 hrs per day gently warming where I don't need heat. It would be nice to think that at night or when we are out, the electric meter was stationary. The only fly in the ointment is the different voltages that many of these things are designed for.

The idea is sound technically and can be extended to run model train sets etc. But its high capital cost makes no financial sense for two basic reasons. Firstly the vast majority of electrical energy is required for heating and work loads (we are not all geeks with electronics everywhere) and, secondly, the percentage drop in electricity consummed has to be halved for money saved due to the very aggressive "reducing block tariffs" that we have for our utility bills.

I don't see it happening. The conversion figures from AC to DC are worst case, and not representative of most modern supplies. In my house I have DC supplies running at 19V 3A for my laptop, down to 3.3V for my Bluetooth headphones, other voltages include 6V, 9V and 4.5V. So I would need DC-DC converters to switch all these, run my devices using non standard chargers, and worst of all if it was running at 12V around the house run thick cables because there will be voltage drops when I've got a couple of high current loads. Oh and I'll still need real mains sockets for stuff that uses real power.The money would be better spent on better inverter designs, and panels that can be disguised as standard roofing tiles and get better efficiency!

Ok we can generate 12v from wind turbine and solar panels, but having this set up is great. Where I have run into trouble is storage i.e. batteries. The inverters are really improving of late, but the batteries are still to large and take up to much room not to mention acids etc.

The problem with any DC network for home use will be getting manufacturers to agree on a standard voltage, and a standard socket/plug.Even if you suggest 12V with a car cigar lighter plug - as on most cars, caravans and boats - you can bet that around the corner the major car manufacturers are planning a move from 12V to 60V, or whatever, that will scupper the whole plan.More efficient 'plugtop' power supplies and better designed products would reduce the power wasted in so many current consumer electronic products.The earlier comments on washing machines and driers are good point too.

I almost worked for a company that made inverters for motor home microwave ovens. Until they firmly believed it had to work at 50/60 Hz. If the oven transformer was built for 400 Hz to 5kHz. like the Ham radio DC supplies of old time, it would be much more efficient.

I think what Moxia's research has revealed is that we can combine both AC and DC in our homes. Its easy to split your DB Box to have DC operate low voltage lighting, televisions, laptops, mobile phones. The AC current can always power up power hungry devices, this way if there should be an emergency you still have some resources left.

The other issue will be to have manufacturer's of electronic components have selectable switches on their devices for choice of DC or AC use by the end user.

At last the greeny boppers will get to kid themselves on they are saving the planet whilst running all the low volt must haves on DC generated on the roof for free. Add the cost of distributing the low volt DC around the house to the original ring main costs and I doubt it will catch on in main stream house building. Great idea, but not worth the millions in research. As has been mentioned almost every pleasure craft has a version lying atop the wheel house

HI we have been doing this for over 10 years in motor homes and caravans What we do is install larger leisure batteries and feed the DC current in an via a controller feed the 12 volt system of the leisure-side of the vehicle

I am doing a similar system on my house at the moment. But it does not have to cost a lot of money. You can produce a 12Volt system for approx £500. With this system you can run all 12V Led lighting in your house; charge all low DC power devices like mobile phones, mp3 players etc and with a small inverter charge or run small ac devices.